But the Nigeria international has only picked up two bookings so far this season and has not seen red since January 2008 against Everton.
Obi puts the dramatic improvement in his disciplinary record down to adapting to the English game.
"English football is always something crazy and, when you come into the Premier League, you must adapt to it somehow," said Obi.
"I guess the timing of those tackles was the area I had to improve and I think I've dealt really well with it.
"I think it was the hunger I had for the games, the enthusiasm, that meant I did not know how to restrict myself from going into tackles at the wrong moment.
"It took me a bit of time to get used to things but now it has been two years with no red cards and I hope I can continue like that.
I think it was the hunger I had for the games, the enthusiasm, that meant I did not know how to restrict myself from going into tackles at the wrong moment. Chelsea and Nigeria midfielder Jon Mikel Obi "I always try to keep my aggression but not get booked.
"But when you play in the position I play, sometimes you have to commit because the team will be in danger if you don't."
Obi was the last of Chelsea's four Africa Cup of Nations players to return to England last month.
His Nigeria side were beaten in the semi-finals of the competition but won their third-place play-off 1-0 against Algeria.
Obi was a 78th-minute substitute in that game but he has slotted straight back into the Chelsea side since he returned, including a fine performance against Arsenal.
He was outstanding against Cardiff in Chelsea's 4-1 FA Cup fifth-round victory on Saturday and is now hoping for a hat-trick of triumphs in the competition.
Obi has curbed his indiscipline Chelsea face the winners of the replay between Manchester City and Stoke in the last eight.
Obi has won the trophy in two of his three full seasons at Stamford Bridge - being singled out for impressive performances in both the 2007 and 2009 finals.
"I want to do well because I always want to win," added Obi.
"But maybe the final feels a bit more special and a good performance there shows people how much you want to win the trophy.
"The game is the really special part of the day if you get to the FA Cup final.
"That's what leads you to winning the trophy and everything else comes from that - the build-up and the celebrations just make it more special.
"I think playing the FA Cup, whatever round you are in, always feels very special."